This research program seeks to contribute to the understanding of conjugate eye movements by studying the electrophysiological responses of cells in an extraocular muscle (EOM) nucleus. Recent experimental findings point to the participation of the internal medullary lamina of the thalamus (IML), the superior colliculus (SC) and the pontine reticular formation (PPRF) in the initiation and integration of eye movements. It has also been shown that the SC and PPRF have inhibitory influences on antagonist muscles as well as excitatory influences on the agonist during conjugate eye movements. Other investigations have indicated the presence of "interneurons" with an unknown function, and motoneurons that may show differing functional characteristics, in EOM nuclei. It is my contention that the recording of intracellular potentials in abducens nucleus motoneurons and "interneurons" evoked by stimulation of the IML, SC and PPRF will help clarify: 1) the functional role and connections of the "interneurons," 2) the excitatory and inhibitory influences of the IML, SC and PPRF on abducens neurons, 3) the role of particular stimulation sites within a structure, and the effect of initial eye position, on abducens neuron responses, 4) the possibility that particular abducens motoneurons have differing functional characteristics. It is expected that this research program will contribute to the establishment of a basic electrophysiological framework pertinent to the understanding of coordinated eye movements. BIBLIOGRAPHIC REFERENCE: Goldberg, S.J., Lennerstrand, G. and Hull, C.D. 1976. Motor unit responses in the lateral rectus muscle of the cat: Intracellular current injection of abducens nucleus neurons. Acta physiol. scand. 96:58-63.